FR2789384A1 - Glass-making raw materials preparation involves thermal conversion of silica and halides, especially chlorides, or sulfates or nitrates of alkali and/or alkaline earth and/or rare earth metals using immersed burner - Google Patents

Abstract

Preparation of compounds based on silicates of alkali metals, such as Na and K, and/or alkaline earth metals, such as Ca and Mg, and/or rare earth metals, e.g. Ce, optionally in the form of mixed silicates involves thermal conversion of silica and halides, especially chlorides, or sulfates or nitrates of the above metals, such as NaCl, KCl and CeCl4, using immersed burner(s). The combustion supporter supplied to burner(s) comprises air, oxygen-enriched air or oxygen. Fuel, e.g., natural gas or hydrogen, is supplied to the burners. The fuel can be supplied in the form of a solid containing carbon, for example charcoal or any material containing hydrocarbon polymers, optionally chlorinated. The combustion created by burner(s) assures at least partial mixing of the silica and halides, generates at least part of the water necessary for conversion, and generates halogen derivatives, notably HCl or Cl2, or H2SO4. The formed silicates are treated, namely granulated, before being supplied in the heated state to a glass furnace. Independent claim are given for: (a) apparatus for implementing the above process; (b) use of the above process or apparatus for forming vitrifiable raw materials for glass production; (c) use of the above process or apparatus for forming raw materials, especially Na2SiO3 for detergent production; (d) use of the above process or apparatus for forming raw materials, especially Na2SiO3 for precipitated silica production; (e) use of the above process or apparatus for vitrifying or rendering inert chloro-organic wastes, preferably by conversion of silica and raw material containing at least alkaline earth metals; and (f) a process for production of glass containing silica and alkali(ne earth) oxides of the type Na2O, K2O, CaO and MgO and /or rare earth oxides of the type CeO2.

Description

PROCESS FOR THE PREPARATION OF RAW MATERIALS

FOR THE MANUFACTURE OF GLASS

  The invention relates to a process for the preparation of some of the

  materials that can be used to make glass.

  In the context of the present invention, the term "raw materials" includes all materials, batch materials, natural ores or synthesized products, materials derived from cullet type recycling, etc.

  , which can enter into the composition coming to feed a glass furnace. Likewise, "glass" is understood to mean glass in the broad sense, that is to say encompassing any material with a vitreous matrix, vitroceramic or ceramic. The term "production" includes the essential melting stage of the raw materials and possibly all the subsequent / complementary stages aimed at refining / conditioning the molten glass with a view to its final shaping, in particular in the form of flat glass (glazing ), hollow glass (flasks, bottles), glass in the form of mineral wool (glass or rock) used for its thermal or sound insulation properties or even possibly glass under..DTD: form of so-called textile threads used in the reinforcement.

  The invention is particularly interested in the raw materials necessary for manufacturing glasses having a significant content of

  alkaline, especially sodium, for example glasses of the silico-

  soda-lime used to make flat glass. The raw material currently most frequently used to provide sodium is

  sodium carbonate Na2CO3, a choice which is not without drawbacks.

  In fact, on the one hand, this compound provides only sodium as a constituent element of glass, the whole carbonaceous part decomposing in the form of CO 2 releases during melting. On the other hand, it is an expensive raw material, compared to others, because it is a synthetic product, obtained by the Solvay process from sodium chloride and limestone, process imposing a certain number of '' steps

  manufacturing and not very energy efficient.

  This is the reason why different solutions have already been proposed to use as a sodium source not a carbonate but a silicate, possibly in the form of a mixed silicate of alkalines (Na) and alkaline-earth (Ca) that we prepare beforehand. The use of this type of intermediate product has the advantage of bringing together several of the constituents of the glass, and of eliminating the decarbonation phase. It also makes it possible to accelerate the melting of raw materials as a whole, and to promote their homnogenization during melting, as indicated, for example, in patents FR-1,211,098 and FR-1,469,109. However, this route poses the problem of manufacturing this silicate and does not offer a synthesis mode

fully satisfactory.

  The object of the invention is therefore to develop a new manufacturing process for this type of silicate, which is in particular capable of ensuring industrial production with reliability, efficiency and cost.

acceptable.

  The invention firstly relates to a process d (the manufacture of compounds based on alkali silicates such as Na, K and / or based on rare earths like cerium Ce, optionally in the form of mixed silicates associating alkali and / or rare earths of alkaline earths such as Ca or Mg. This process consists in synthesizing these compounds by conversion of silica and halide (s), in particular of chloride (s), of said alkali and / or of said rare earths, of NaCl, TKCI or CeCI type (and

  optionally halides, in particular alkaline chlorides

  earthy, in the case of mixed silicates), the heat input necessary for this conversion being supplied, at least in part, by one (s)

submerged burner (s).

  We understand here by the term "silica" any compound containing mainly silica (silicon oxide) SiO2, even if it can also contain other elements, other minority compounds, which is particularly the case when '' we use materials

natural sand type.

  Here we understand by "submerged burners", burners configured so that the "flames" that they generate or the combustion gases from these flames develop in the reactor where the conversion takes place, within the mass of the materials being transformed. Generally, they are arranged so as to be flush with or slightly protrude from the side walls or from the bottom of the reactor used (we are talking about flames here, even if they are not strictly speaking of the same "flames" as those produced by

  overhead burners, for simplicity).

  The invention has thus found a particularly judicious technological solution for achieving industrial exploitation of a chemical transformation already proposed by Gay-Lussac and Thénard, namely the direct conversion of NaCl to soda, involving the reaction of NaCl with high silica. temperature cn presence (- 'water according to the following reaction: 2 NaCl + SiO2 + H20 4 Na2SiO3 + 2 HCI the principle consisting in extracting the soda by formation of silicate, the equilibrium being constantly shifted in the direction of decomposition

  NaCl because the two phases are not miscible.

  This reaction has hitherto posed considerable processing problems, linked to difficulties in producing an intimate mixture of the reagents, and in ensuring their renewal during manufacture, also linked to difficulties in removing HCl without it reacts again on the silicate formed, to extract the silicate and to manage to provide

sufficient thermal energy.

  Use submerged burners to provide this energy

  thermal solves most of these difficulties at the same time.

  Indeed, having recourse to heating by submerged burners had already been proposed to ensure the melting of vitrifiable materials for making glass. We can for example refer to patents US-3,627,504, US-3,260,587 or US-4,539,034. However, use it in the precise context of the invention, namely the synthesis of silicates from salts, is extremely advantageous: - this mode of combustion indeed generates water, water which, as we have seen above, is essential for the desired conversion. Thanks to the immersed burners, it is thus possible to manufacture in situ the water necessary for the conversion, at least in part (even if, in certain cases, an additional supply of water may be necessary). We are also sure to introduce water into the other starting materials, namely silica and salt (s) (we will designate for the sake of brevity by the term "salts" all

  halides such as alkali, rare earth and alkaline chlorides

  possibly earthy, used as starting reagents), which is of course conducive to favoring the reaction, - moreover, the combustion of the submerged burners causes in the materials under reaction strong turbulence, strong convection movements around each of the "flame (s)" and / or each of the gas jets from each of the burners. In fact, it will therefore ensure, at least in part, a strong stirring between the reagents, stirring necessary to guarantee an intimate mixture between the different reagents, especially those introduced in solid (powdery) form such as silica and the (s) salt (s), '- submerged burners are also particularly advantageous from a strictly thermal point of view, because they bring heat directly where it is needed, namely in the mass of the products under reaction, thus minimizing any loss of energy, and because they are powerful enough, effective so that the reactants can reach the relatively high temperatures necessary for their melting / conversion, namely temperatures of at least 1000 C, in particular of the order of 1200 C, they are also a particularly environmentally friendly mode of heating, minimizing any possible emission of

NOx type gas in particular.

  We can therefore conclude that the efficiency of these burners at all levels (quality of the mixture, excellent heat transfer, one of the reactants generated in situ) means that the conversion is greatly favored, and this without necessarily needing '' reach temperatures

extremely high.

  The oxidizer chosen to supply the submerged burner (s) may simply be air. Preferably, however, an oxidizer is favored in the form of air enriched in oxygen, and even in the form substantially of oxygen alone. A high oxygen concentration is advantageous for various reasons: this reduces the volume of combustion fumes, which is favorable from an energy point of view and avoids any risk of excessive fluidization of the materials in the course of the reaction which can cause splashes on the superstructures, the roof of the reactor where the conversion takes place. In addition, the "flames" obtained are shorter, more emissive, which allows faster transfer of

  their energy to the materials being melted / converted.

  Regarding the choice of fuel for the submerged burner (s), two ways are possible, alternative or cumulative: 'one can choose a liquid fuel of the fuel oil type, or gaseous of the natural gas type (mostly methane), propane, hydrogen, - one can also use a fuel in solid form containing carbon, for example coal or any material containing

  hydrocarbon polymers, possibly chlorinated.

  The choices made for the oxidizer and fuel for submerged burners influence the nature of the products obtained, apart from silicates. Thus, when the burners are supplied with oxygen and natural gas, the following two reactions are schematically produced: (starting from the simplest case where we want to make Na silicate from NaCl, but we can transpose it to all the other cases, where it is a question of making silicates of K, of Ce, containing Ca or Mg, etc ...): (a) 2 NaCI + SiO2 + H20 -) Na2SiO3 + 2 HCl (b) CH4 + 2 02 -4 C02 + 2 H20 These two reactions can be combined in one (c) 4 NaCl + 2 SiO2 + CH4 + 2 O2 "2 Na2SiO3 + 4 HCl + CO2 When using a hydrogen fuel rather than natural gas, there is no more CO2 emission, the overall reaction is written (d) 4 NaCl + 2 SiO2 + 2 H2 + O2 "2 Na2SiO3 + 4 HCl When using a fuel in solid form, containing carbon, always with an oxidizer in the form of oxygen, the following reaction is written: (e) 2 NaCI + 3/2 02 + C + SiO2 - Na2SiO3 + C12 + C02 This time, so we no longer produce HCI, but chlorine C12

  as conversion byproducts.

  It is therefore clear from these various balance-sheet reactions that the conversion envisaged by the invention also generates halogenated derivatives, in particular upgradable chlorinated derivatives such as HCl or Ci, which are found in combustion fumes. Two ways of use are possible: -> one consists in reprocessing them as effluents. It is thus possible to neutralize HCl with calcium carbonate CaCO2, which amounts to manufacturing CaCl2, possibly recoverable (for snow removal from roads for example), À-- the other way consists in considering the conversion according to the invention as a means of industrially manufacturing HCI or Cl2 basic chemicals widely used in the chemical industry. (In particular, HCl or Cl2 manufactured according to the invention can be substituted for the chlorine obtained by electrolytic means which is necessary for the manufacture of chlorinated polymers of the PVC, polyvinyl chloride type). In this case, it is then necessary to extract them from the fumes and thus establish a fillare of industrial production of HCl or Cl2, for example by implanting the device for implementing the method according to the invention directly in a site of the chemical industry. needing this type of chlorine products. Valuing the chlorine derivatives thus formed makes it possible to further lower the cost of the raw materials carrying alkalis necessary for the manufacture of glass. A first outlet for the silicates produced according to the invention relates to the glass industry: they can replace, at least in part, the traditional raw materials providing alkalis or rare earths, with very particularly with regard to sodium, at least partial substitution of CaCO3 with Na2SiO3. It is therefore possible to use the silicates of the invention to feed a glass furnace, and this in particular in two different ways: - the first way consists in treating the silicates formed to make them compatible with use as vitrifiable raw materials for glass furnace : it is therefore a question of extracting them from the reactor and generally of putting them "cold" in the pulverulent solid phase, in particular by a granulation step according to techniques known to the glass industry. There is therefore a complete disconnection between the silicate manufacturing process and the glass manufacturing process with appropriate shaping, and possible storage / transport of the silicate formed before it feeds the glass furnace, - the second way consists to use the silicate (s) formed according to the invention "hot", that is to say to use a process d (the manufacture of glass incorporating a prior step of manufacturing the silicate coming to feed , still in fusion, the glass furnace. One can thus manufacture silicate in a reactor connected to the glass furnace, constituting one of its "upstream" compartments as opposed to its possible compartments

  "downstream" intended for the refining / conditioning of the glass once it has melted.

  In these two cases, the glass furnace can be of traditional design (for example electric melting furnace by submerged electrodes, furnace with aerial burners operating with lateral regenerators, loop furnace, and any type of furnace known in the industry glass roof thus including the furnaces with submerged burners), with a design and an operating mode slightly adapted to a melting process without carbonate or with less carbonate than for

standard mergers.

  It should be noted that certain silicates other than sodium silicate are also very advantageous to manufacture according to the invention. Thus, the invention makes it possible to manufacture potassium silicate from KCl, which is, economically at least, very advantageous as a raw material carrying Si and K for manufacturing so-called "mixed alkaline" glasses, that is ie containing both Na and K. These glasses are used in particular for making touch screens, television screen glasses, lead glasses, glasses for plasma display screen ("Plasma display Panel" in In the same way, the invention makes it possible to more economically manufacture special glasses containing additives for which chlorides are less expensive than oxides. This is the case for rare earths such as

  cerium: the presence of cerium oxide conferring anti U.V. properties

  with glasses, and rare earths of this type also enter the

  composition of special glasses with high elastic modulus for hard disk.

  The invention thus makes it possible to have a raw material carrying Si and

  This, cerium silicate, at a moderate cost.

  Another additional advantage of the invention is that the silica introduced at the start undergoes a certain deferrization during the conversion into silicate because the iron chloride is volatile: the glass produced from this silicate, using at least a certain amount of this silicate will therefore tend to be lighter than a glass not using this type of silicate at all. This is aesthetically interesting, and tends to increase the solar factor of the

  glass (in a "flat glass" application).

  A second outlet for the silicates produced according to the invention (apart from being used as raw materials for glass furnaces), more particularly sodium silicate, relates to the detergent industry; sodium silicate Na2SiO3 frequently used in the composition of

detergents / detergents.

  A third outlet for the silicates (and optionally the chlorinated derivatives) formed according to the invention relates to the preparation of specific silicas, commonly referred to as "precipitated silicas" used, for example, in the composition of concretes. It is in fact possible to carry out an acid attack on the silicates formed according to the invention, advantageously with hydrochloric acid HC1 which has also been formed by the conversion according to the invention, so as to precipitate silica in the form of particles having a particular particle size: the particle size targeted is generally nanometric (1 to 100

nm for example).

  The sodium chloride also formed during the precipitation of the silica can advantageously be recycled, again serving as a raw material for the manufacture of silicate according to the invention very particularly. This is an extension of the invention, where, starting from a particulate silica of "large" particle size (of the order of a micron or larger for example), particulate silica is again obtained but of much smaller particle size, this, - control and this size dimension opening the way to a wide variety of uses in

  materials used in industry.

  Another interesting application of the process relates to the treatment of chlorinated waste, very particularly of chlorinated and carbonaceous waste such as chlorinated polymers (PVC, ...) fusion by submerged burners, according to the invention, can pyrolyze this waste, with as ultimate combustion products CO2 and HCl, HCl possibly being, as we have seen previously, neutralized or recovered as it is. It can be noted that this waste can also then serve as solid carbon-carrying fuel, which in fact can make it possible to reduce the quantity of fuel to be injected at the level of the burners. (It can be other types of waste such as foundry sands). The pyrolysis of these different wastes is again interesting from an economic point of view, since their otherwise necessary treatment cost is deducted from the cost of producing the silicates according to the invention. Rather than pyrolysis

  real waste, it can also be vitrification.

  The subject of the invention is also the device for implementing the method according to the invention, which preferably comprises a reactor equipped with burner (s) submerged (s) and at least one means for introducing d ( silica and / or halides below the level of molten materials,

  in particular in the form of one or more worm feeders.

  It is thus possible to introduce directly into the mass (products in the process of melting / reaction at least those of the starting reagents capable of vaporizing before having time to react: we think here

  especially sodium chloride NaCl.

  Preferably, the walls of the reactor, in particular those intended to be in contact with the various reactants / reaction products involved in the conversion, are provided with refractory materials lined with a metal lining. The metal must be resistant to various corrosive attacks, especially here those caused by HC1. We therefore prefer titanium, a metal of the same family or an alloy containing titanium. Advantageously, provision can be made for all the elements inside the reactor by opening into the latter to be based on this type of metal or surface protected by a coating of this metal (the oven chargers, the submerged burners). It is preferable that the walls of the reactor, and in particular also all the metal parts inside the latter, be associated with a cooling system by circulation of fluid, of the water box type. The walls can also be entirely metallic, with or without very few of the standard refractories used for the construction of ovens

glassmakers.

  The walls of the reactor, for example, define a substantially cubic, parallelepiped or cylindrical cavity (catreated, rectangular or round base). Advantageously, it is possible to provide for several points of introduction of the starting reactants, for example distributed regularly in the side walls of the reactor, in the form in particular of a number of ovens. This multiplicity of supply points makes it possible to limit the amount of reagents at the level of each

  of them, and to have a more homogeneous mixture in the reactor.

  The reactor according to the invention can also be equipped with various means for treating chlorinated effluents, in particular for recovering or neutralizing effluents of the C12, HC1 type, and / or means for separating solid particles from gaseous effluents, in particular 't based on metal chlorides. These means are advantageously

  arranged in the chimney (s) evacuating the fumes from the reactor.

  Finally, the object of the invention is also a process for producing glass containing silica and alkali metal oxides of the Na2O, K20, O type or rare earth oxides of the CeO2 type, by melting vitrifiable materials o l 'heat input necessary for said fusion comes at least in part from submerged burners. Here, the invention resides in the fact that the raw materials carrying alkalis of the Na, K type, or of rare earths of the Ce type are at least partly in the form of halides, in particular chlorides, of said elements, such as NaCl , KCl, CeCI4. This is the second major aspect of the invention, where, in a way, everything happens as if the previously described silicate were manufactured "in situ" during the very process of melting vitrifiable materials to make glass. The economic interest in replacing all or part, in particular, of sodium carbonate by NaCl is clear. We find here the same advantages as those mentioned above, concerning the manufacture of silicate independently of that of glass, namely in particular the lower iron content of the glass, the possible recoveries of the chlorinated (halogenated) derivatives produced, the pyrolysis or vitrification of waste possibly

  also suitable for use as solid fuel ...

  The invention will be detailed below using an embodiment illustrated by the following figure: Cl figure 1: a schematic installation for manufacturing silicate

sodium according to the invention.

  This figure is not necessarily to scale and has been

  extremely simplified for clarity.

  It represents a reactor 1 comprising a sole 2 of a rectangular elm pierced regularly so as to be equipped with rows of burners 3 which pass through it and enter the reactor over a reduced height. The burners are preferably covered with titanium and cooled with water. The side walls are also water cooled and have a coating of electrofused refractories 5 or are entirely metallic based on titanium. The level 5 of the materials in the course of reaction / melting is such that the worm feeders 6 introduce

  the reagents at the side walls below this level.

  The hearth comprising the burners may have a thickness of deeper refractories than the side walls. She is

  pierced with a tap hole 10 to extract the silicate.

  The vault 8 can be a suspended flat vault made of refractory materials of the mullite or zirconia-inullite or AZS (aluminezircone-silica) type or of any ceramic material resistant to HCI and or NaCI. It is designed so as to be impermeable to fumes containing HCI: a non-limiting solution to guarantee this impermeability consists in using a ceramic honeycomb structure made up of hollow hexagonal pieces in which an insulator is placed. Sealing is then carried out between the parts on the upper surface, using a low temperature sealant resistant to HCl. It thus protects the metallic support structure. The chimney 9 is also constructed of materials resistant to HCI and NaCI (refractory to oxides, silicon carbide, graphite). It is equipped with a system for separating solid particles which are liable to condense (metal chlorides) and a tower

  recovery of HCl, which are not shown.

  Once the silicate has been extracted from the reactor through the taphole 10, it is conveyed to a granulator, not shown, of the type used in the glass industry or in the sodium silicate industry for

Laundry.

  The purpose of the process is to manufacture a silicate highly concentrated in sodium, which is quantified in a known manner by a molar ratio of Na2O relative to the total (SiO2 + Na2O) at around 50% ", by introducing into the reactor by the oven conveyors a mixture of sand (silica) and NaCl 1. These two reagents can also be introduced separately, and may have been optionally preheated before

introduction into the reactor.

  Preferably, the burners 3 are supplied with oxygen and

natural gas or hydrogen.

  The viscosity of the mixture during fusion / reaction and the high reaction speed obtained thanks to the technology of the submerged burners allow to reach high specific draws, to give a

  order of magnitude of for example at least 10 tonnes / day.

  In conclusion, the process of the invention opens a new way of manufacturing at moderate cost silicates, especially sodium, potassium and cerium silicates. It also falls within the context of the present invention to use mutadis mutandi the same process for no longer manufacturing alkali or rare earth silicates but titanates, zirconates, aluminates of these elements, (possibly

mixed with silicates).

  A metal, in particular belonging to the transition metals and more particularly from column 4b of the periodic table such as Ti, Zr or to the metals of column 3a of the periodic table as AI, is at least partially substituted for silicon. The advantage

  of such a substitution is that the product obtained is soluble in water.

  The attack on the selection of these products in aqueous solution, in particular by using hydrochloric acid formed during the conversion, leads to the precipitation of particles no longer of silica, as mentioned above in the text, but of metal oxide particles. corresponding as TiO2, ZrO2, A1203, generally having nanometric dimensions as when starting from silica, and which find numerous applications in industry. They can thus be used as fillers in polymers, in concretes, and incorporated into ceramic or glass-ceramic materials. We can also exploit their photocatalytic properties: particularly targeted are TiO2 particles (which can be incorporated into photocatalytic coatings with anti-fouling properties for any material

architectural, glazing, etc ...).

  To manufacture according to the invention these titanates, zirconates, aluminates, the process described above is directly transposed to obtain the silicates, starting from halides of the NaCl type and oxides

  metallic of the metals involved (TiO2, ZrO2, A1203, ...).

  Alternatively, it is possible to use as starting material (the conversion carrying the metal directly the halide of the said metal and no longer its oxide. It may in particular be chloride such as TiC14, ZrCl4, AIC13 (it is also possible to choose initially carrying the metal, a mixture of oxide and chloride of the said metal). In this case, the alkali-bearing material may be the same halogen of the NaCl type used to make silicate, this salt possibly being supplemented

  or replaced with soda when the alkaline sodium is involved.

  As in the case of "precipitated silica", this extension of the process according to the invention can thus be seen as a means of modifying, in particular reducing the particle size of a metal oxide, so as to open it to other applications in industrial materials.

Claims (16)

  1. Process for the manufacture of compounds based on alkali silicate (s) such as Na, K and / or rare earths such as Ce, optionally in the form of mixed silicates associating the alkali (s) and the ( the) rare earth (s) with alkaline earth metals such as Ca, by conversion of silica and of halides, in particular of chloride (s), of said alkalis and / or of said rare earths and / or of said alkaline earth metals , such as NaCI, KCJ, CeCI14, characterized in that the heat input required for the conversion is   supplied, at least in part, by a submerged burner (s).   2. Method according to claim 1, characterized in that the submerged burner (s) are supplied with an oxidant in the form of air,   air enriched with oxygen or oxygen.   3. Method according to one of the preceding claims, characterized   in that the submerged burner (s) are supplied with fuel in the form of natural gas, fuel oil or hydrogen and / or in that they are brought close to said burner (s) ( s) fuel in solid form, in particular containing carbon-based materials based on polymers,   possibly chlorinated, or based on carbon.   4. Method according to one of the preceding claims, characterized   in that the combustion created by the submerged burner (s) provides the   less partly the mixing of the silica and the halide (s).   5. Method according to one of the preceding claims, characterized   in that the combustion created by the submerged burner (s) generates   less the water required for conversion.   6. Method according to one of the preceding claims, characterized   in that the conversion also generates halogenated derivatives,   in particular recoverable chlorine derivatives such as HCI or C12.   7. Method according to one of the preceding claims, characterized   in that the silicate (s) formed are treated to make them compatible (s) with use as a vitrifiable raw material (s) for   glass furnace, treatment comprising in particular a granulation step.   8. Method according to one of claims 1 to 6, characterized in that   that the silicate (s) formed (s) feed (s) hot a glass furnace.   9. Device for implementing the method according to one of   previous claims, characterized in that it includes at least   a reactor (1) equipped with submerged burner (s) (3) and at least one means for introducing the silica and / or the halide (s) below the level of the materials being melted, especially in the form of an oven (s) (6) worm. 10. Device according to claim 9, characterized in that the walls (2, 4) of the reactor (1) in particular those intended to be in contact with the various reactants / reaction products involved in the conversion are provided with refractory materials for example of the electrofused type or of refractory materials lined with a metal lining of the titanium type or are based on this type of metal, and are preferably associated, at least for the side walls (4), with a system   cooling by circulation of water type fluid.   11. Device according to claim 9 or claim 10, characterized in that the walls of the reactor (1) define a cavity   substantially cubic, parallelepiped or cylindrical.   12. Device according to one of claims 9 to 11, characterized in   that the reactor (1) is equipped with means for treating chlorinated effluents, in particular means for recovering FICI or Cl2 or neutralizing HCl and / or means for separating in effluents   gaseous solid particles, for example based on metal chloride.   13. Use of the method according to one of claims 1 to 8 or of   device according to one of claims 9 to 12 for preparing materials   vitrifiable raw materials for the manufacture of glass.   14. Use of the method according to one of claims 1 to 8 or of   device according to one of claims 9 to 12 for preparing materials   raw materials, in particular sodium silicate Na2SiO3, for manufacturing detergents.   15. Use of the method according to one of claims 1 to 8 or of   device according to one of claims 9 to 12 for preparing materials   raw materials, in particular sodium silicate Na2SiO3, for manufacturing precipitated silica.   16. Process for obtaining glass containing silica and alkali metal oxides of the Na20, K20 type or rare earth oxides of the CeO2 type by melting vitrifiable materials where the heat input necessary for said melting comes at least for part of submerged burner (s), characterized in that the vitrifiable materials carrying alkalis of the Na, K type or of rare earths of the Ce type are at least partly in the form of halides, in particular chlorides of the said elements , such as NaCl, KCI, CeCl4.